As Angelo said, you might best be served by hiring keyboard players to come and play melodies, riffs, etc. for you. IOW, build up your own "sample library".

The problem with getting all your "notes" from the Karma, Triton or whatever is that EVERYONE with access to those instruments can do the same thing. Unless you're a clever programmer, your stuff will come out like anyone else who uses the instrument.

You might look at some of the Remixer boxes out there. Yamaha RM1x, QY-series, etc. I provided a lot of content for those instruments and they can do much more than playback "canned rhythm tracks".

Try looking at some of the more "esoteric" comptuer synthesis programs like "Metasynth". Its very cool and will lead you to more than a few uncommonly heard tones.